Device for drawing curves through a plurality of plotted points



March 19, 1957 R. D. ELKIN 2,785,472

DEVICE FOR DRAWING CURVES THROUGH A PLURALITY OF PLOTTED POINTS Filed April 18, 1955 22 ATTORNEYS United States Patent DEVICE FOR DRAWING CURVES THROUGH A PLURALETY F PLOTTED POINTS Robert D. Elkin, Birmingham, Mich.

Application April 18, 1955, Serial No. 502,119

3 Claims. (Cl. 33-177) This invention relates to a device for drawing smooth curves through a plurality of plotted points.

One object of the invention is to provide apparatus for drawing smooth curves through a plurality of plotted points which will greatly expedite the operation and which produces a curve which is smooth and accurate.

Another object of the invention is to provide apparatus for accomplishing the above result which is composed of a relatively few simple parts, easy to operate and relatively inexpensive to manufacture.

Gther objects of the invention will become apparent as the following description proceeds especially when taken in conjunction with the accompanying drawing, wherein:

Figure 1 is a perspective view of apparatus constructed with the present invention.

Figure 2 is a sectional view taken along the line 22 on Figure 1.

Figure 3 is a sectional view taken along the line 3-3 on Figure 1.

Figure 4 is a sectional view taken along the line 4-4 on Figure 3.

Figure 5 is a sectional view taken along the line 55 on Figure 3.

Figure 6 is a fragmentary plan view of a portion of the device.

Figure 7 is a sectional view taken along the line 7-7 on Figure 6.

Referring now more particularly to the drawing and specially to Figure 1 thereof, there is shown an elongated plate or support 10 and a flexible resilient spline or band 12, both supported on the top surface of a table 14. The band 12 may be of any suitable material which is both flexible and resilient and tends to return to a straight line condition. The bend may, for example, be of a suitable plastic material and should be sufficiently flexible and resilient so that it will not take a permanent set even though curved in a rather abrupt are.

One end portion 1'3 of the plate 10 has a recess 15 in the underside and the end portion 17 of the band 12 ex tends into the open front of the recess and is pivotally connected to the vertically extending pin 16 which extends through the plate having the pivot portion extending downwardly into the recess 15 for pivotal connection with the band. The pivoted end of the band has its bottom surface flush with the bottom of the plate.

The opposite end portion 19 of the plate also has a recess 18 in the underside which extends entirely to the adjacent end edge of the plate except for the front edge corner portion which is not cutaway or recessed. The end portion 22. of the band extends into the open front of the recess 18. An adjustable member is carried by the end portion 19 of the plate for engagement with the outer edge of the band and this adjustable member comprises a screw 24 threadedly engaging the front corner portion 20 of the plate, and an adjustment block 26. The inner end portion of the screw 24 is unthreaded and fits within a socket in block 26, the connection perice mitting the screw to rotate relative to the block. The block is retained on the screw by the tension of the spline against which it bears. This abutment block has a groove or recess along the inner edge, the recess being formed by the vertically extending abutment surface 28 engageable with the outer edge 27 of the band and the downwardly facing surface 3t) which extends inwardly from the upper edge of the abutment surface 23 for holddown engagement with the top surface of the band.

A plurality of members are arranged on the plate between the pivot 16 and the recess 18 in spaced relation to each other lengthwise of the plate. are indicated by the numeral 32 and comprise slide blocks 34- of inverted T shape slidably supported in the correspondingly shaped grooves 36 in the top surface of the plate which extend transversely of the plate and parallel to one another. The blocks have been removed from certain of the grooves in Figure 1 for clarity. Each slide block has a longitudinally extending bore 38 therethrough in which extends a rod 40 adjustably secured to the block in selected axial and rotative positions by a set screw 42. Abutment members or heads 44 are pro vided, each having a socket into which fits the reduced outer end portion of each rod. The tension of the spline or band holds the head on the rod. The heads 44 have flat horizontal bottom surfaces 46 extending in a plane parallel to the bottom surface of plate it). A threaded fastener 48 extends vertically into each head through the bottom surface thereof and rotatably mounts a wheel 50 on the head. The outer periphery 52 of each wheel is adapted to engage the inner edge of the band 12 and it will be noted that the wheel is supported on the head rearwardly of the front portion 54 of the bottom surface 46 so that the front portion 54 may engage the top surface of the band and prevent it from bending upwardly out of parallelism with the table top 14.

The members 32 may be releasably secured in selected positions of adjustment with respect to the plate 10. As seen particularly in Figures 1 and 2, the plate has a block 56 welded to the top surface thereof adjacent to each of the grooves 36. in addition, a similar block 58 is welded to one side of each slide block 34 and the blocks 56 and 58 have aligned through passages disposed in the direction of length of the grooves 36. A screw 60 extends through the passages in the blocks 56 and 58 having threaded engagement with the passage in block 56. The screws also have fixed flanges 62 engageable with the inner sides of blocks 58 so that rotation of the screws 6% in one direction will move the members 32 outwardly with respect to the plate, that is toward the band 12. Rotation of the screws in the opposite direction will cause them to move axially inwardly whereupon the compression springs 6 encircling the screws and having their opposite ends abutting the blocks will operate to move the members 32 inwardly.

At points respectively between adjacent members 32, the plate it) is formed with the through passage 66 which extend parallel to each other and in the direction of length of the grooves Screw members 63 have their shanks threadedly engaged in the rear ends of these passages 66 and rods "iii extend through the longitudinal passages in the screw members and through the passages 66 beyond the front edge of the plate. These rods are fixed to the screw members by set screws 72. Abutment members 7d are supported on the outer ends of the rods iii. These abutment members are in the form of plates having the horizontally extending portions 76, the depending flange portions 78 at the outer ends and the upstanding flanges $0 at the inner ends. The abutment members may be secured to the outer ends of the rods "iii in any suitable manner and in the present instance they are supported on annular grooves 32 in the outer ends of the respective These members grooves and retain the members 7d in place on the rods against accidental removal. Obviously, other arrangements may be used, and the flanges 80 may, for example, have unslotted'openiugs loosely receiving the sl fasteners removably secured on the ends of the rods.

As-seen in Figures 2 and 3, the outer top edge of the band isgrooved and the vertically extending surface 34 of thisgroove is adapted to be engaged by the depending flange 78 of abutment member id. While only rods 7% isshown in Figure 1, it will be uuders such rodshaving members 74 thereon extend from each passage 66.

The operation of the deviceshould be readily apparent from the foregoing description. The series of plotted points indicated i i? in Figure l are laid out on the table or possibly they are applied to a sheet of glass, metal, plastic material and/ or glass and paper which is laid upon the table. The plate it is then placed upon the table top to-one side of the series of plotted points and by suitable manipulation of the members 32; and 7d it is possible to shape the resilient band to extend in a smooth curve along the plotted points. The members 3?. apply an outward force on the inner edge of the band and the members "it? apply an inward force on the band by reason of their engagement with the outer edge of the band, more particularly the outwardly facing surface 4 of the band.

Since these adjustingmembers occur at frequent intervals along the length of the plate, it will be apparent that a smooth accurate curve may be obtained. Moreover, since each alternate member, such as members 3 2, apply an'outward force upon the'band and the remaining bers it? between the members 3 apply an inward force upon the band, a highly satisfactory result can be obtained in a fairly short period of time The end portion 22 of the band is also capableof adjustment by means of the adjusting member 24.

The end 22 of the band or spline may, of course, be taken out of recess 18 to plot a particular series of points, and by suitable manipulation of the rods and *f@ the spline is shaped to follow the points.

The drawings and the foregoing specir cation constitute a description of the improved device for drawing smooth curves through a plurality of plotted points in such full, clear, concise and exact terms as to enable any person skilled in the art to practice the invention, the scope of which is indicated by the appended claims.

What i claim as my invention is:

1. In apparatusfor drawing curves through a plurality of plotted points, an elongated flexible band adapted to be supported on a table, means for shaping said band to extend in a smooth curve along the plotted points includ ing a supportadapted to be positioned on the table at the inner side of said band, a plurality of members extending late ally outwardly from said support in spaced relation to each other and engageable with said band, said members having abutment parts on their outer ends, the abut-- merit parts of certain of said members having generally L-sha ed recesses on the undersides opening 'vardly and outwardly, ea, 11 recess having a generally itwardly facing abutment surface engageable with the inner side of said band and having a generally downwardly facing surface extending outwardly from the upper extremity of said outwardly friing abutment surface for hold down engagement with the top of said band, the abutment parts of the remaining members having generally L-shaped recesses on the undersides opening downwardly inwardly, each of the last-mentioned recesses having a genorally inwardly facing abutment surface engagcable with wardly facing surface extending inwardly fromthe upper' extremity of said inwardly facing abutment surface for hold down engagement with the top of said band, and means for securing said members to said support in selected positions of inward and outward adjustment to correspondingly position the portions of said band engaged by said members. I

2'. In'apparatus fordrawing curves through a plurality of plotted points, an elongated flexible resilient band adapted to be supported on a table, means for shaping said band to extend in a smooth curve along the plotted points including an elongated support adapted to be positioned on the table at theinner side of said band, a plurality of members arranged on said support in spaced relation to each other lengthwise of said support and engageable with said band, each member having an elongated part extending laterally outwardly from said support and supported by the latter for movement in the direction of its length, said members having abutment partson the outer ends of said elongated parts, the abutment parts of alternate members having generally l.- shaped recesses on the undersides opening outwardly and downwardly, each recess having a generally vertical abutment surface facing outwardly for engagement with the inner side of said bandand having a generally horizontal downwardly facing surface extending outwardly from the upper extremity of said vertical surface for hold down engagement with the top of said band, the abutment parts of the remaining members having generally L- shaped recesses on the undersides opening inwardly and downwardly, each of the last-mentioned recesses having a generally vertical abutment surface facing inwardly for engagement with an outer side of said band and having a generally horizontal downwardly facing surface extending inwardly from the upper extremity of said lastmentioned vertical surface for hold down engagement with the top of said band, and means for securing said elongated parts of said members to said support in seected positions of inward and outward adjustment to correspondingly position the portions of said band engaged by said members.

3. In apparatus for drawing curves through a plurality of plotted points, an elongated flexible resilient band adapted to be supported on a table, means for shaping said band to extend in a smooth curve along the plotted points including an elongated support adapted to be positioned on the table at the inner side of said band, a plurality of members arranged on said support in spaced relation to'each other lengthwise of said support and engageable with said band, each member having an elongated part extending laterally outwardly from said support and supported by the latter for movement in the direction of its length, said members having abutment parts on the outer ends of said elongated parts, the abutment parts of alternate members having generally L-shaped recesseson the undersidesopening outwardly and downwardly, each recess having a generally vertical abutment surface facing outwardly for engagement with the inner side of said band and having a generally horizontal downwardly facing surface extending outwardly from the upper extremity of said vertical surface for hold down engagement with the top of said band, the abutment parts of the remaining members having generally L-shaped recesses on the undersides opening inwardly and downwardly, each of the last-mentioned recesses having a generally vertical abutment surface facing inwardly for engagement with an outer side of said band and having a generally horizontal downwardly facing surface extending inwardly from the upper extremity of In)? 4 a References Cited in the file of this patent UNITED STATES PATENTS 326,506 Johnson Sept. 15, 1885 923,875 McDonald June 8, 1909 1,061,345 Weston May 13, 1913 6 Sahm Dec. 2, 1913 Roehrig Mar. 24, 1914 Sibley Feb. 8, 1921 Reich Dec. 7, 1937 Gobel Nov. 19, 1940 Fugua Sept. 12, 1950 FOREIGN PATENTS Great Britain 1906 

